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Why such an insane value for SDMMC_CMDTIMEOUT?

David Littell
Senior III

Why is the value for stm32f7xx_ll_sdmmc.h's SDMMC_CMDTIMEOUT (5 seconds!) so insanely huge as compared to the Reference Manual SDMMC_STA.CTIMEOUT description and the MMC Ncr timing?

2 REPLIES 2

You think that's a long time...

#define SDMMC_DATATIMEOUT                 ((uint32_t)0xFFFFFFFFU)

#define SDMMC_CMDTIMEOUT                  ((uint32_t)5000U)       /* Command send and response timeout */

#define SDMMC_MAXERASETIMEOUT             ((uint32_t)63000U)      /* Max erase Timeout 63 s           */

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David Littell
Senior III

Yeah, I've seen those too. It'd be helpful if there was some commentary explaining such ludicrous values, especially in the case of SDMMC_CMDTIMEOUT, which should rightfully have a value no larger than (64 + 48 + some_small_number) * (SDMMC_CK period).

Hello, ST? 5 seconds checking for bits that should (must!) be set in << 1 mSec?